Automatic circuit breaker



Jan. 25, 1955 K. w. WILCKENS 2,700,711

AUTQMATIC CIRCUIT BREAKER Filed Dec. 14, 1951 mngyg INVENTOR. Y KURT W. WILCKENS HIS flTTORIl/E United States Patent 2,700,711 AUTOMATIC CIRCUIT BREAKER Kurt Walter Wilckens, Morrisville, Pa., assignor to Heinemann Electric Company, Trenton, N. J., a corporation of New Jersey Application December 14, 1951, Serial No. 261,672 9 Claims. (Cl. 200-106) in stress-transmitting position.

The linkage is preferably held against collapse, and in stress-transmitting position, by complementary latch members on the respective links of the linkage and one gap between the poles of an electro-magnet having a coil in circuit with the switch blade.

The flux acting on the armature may be intensified relatively to the current flow by utilizing an electro-magso as to bring bifurcated ends of each pole into position with th potential across the switch blade, it cannot be held in closed position by manipulating the handle, since magnetic flux will be generated and efiect the release of the latch as soon as the overload flows through the switch and electro-magnet.

The principles of my invention, and the best mode in which I have contemplated applying such principles, will 7 2,700,71 l Patented Jan. 25, 1955 further appear from the following description and the accompanying drawings in illustration thereof.

In the drawings Fig. l, is an enlarged side elevation of a circuit breaker embodying my improvements, with parts broken away to show the interior construction; Fig. 2 is a fragmentary view illustrating the movement of the armature to position for unlatching the linkage latch, the linkage not yet having collapsed; Fig. 3 is a detached, perspective view of the linkage, latch and armature, with part broken away to show the latch elements in latching positions; Fig. 4 is a side elevation of the circuit breaker, with parts broken away, and showing the parts in open position ready for re-closing by manipulating the handle; Fig. 5 is an exploded, perspective view of the linkage, latch and armature; and Fig. 6 is an irregular, sectional view taken on the line 6-6 of Fig. 1.

In the embodiment of my invention illustrated in the drawings, a magnetically permeable bracket 1 is secured by bolts 2 to the base of a hollow insulating housing 3. The bracket 1 is provided with a pair of spaced ears 4 containing elongated slots 5 having Walls forming elongated fulcrums for a pintle which passes through an elongated diagonal slot in a switch blade 7. The switch blade 7 has a contact 8 movable into and out of engagement with a yielding contact 9 of a terminal 10 which is secured to the base of the housing 3 by a screw 11. The contact 9 may be connected by a conducting strip 12 with an external line terminal 13.

The switch blade 7 is normally biased toward open position by a bifurcated spring 14, which has a bight 15 looped across the shank of the switch blade, and has legs wound around the pintle 6 and ends engaging the bracket 1.

The switch blade 7 is operable by means of a pivoted handle 16 through linkage comprising links 17 and 18 respectively pivotally connected by pintles 19 and 20 with the handle 16 and switch blade 7 and pivotally connected with one another by a pintle 21. The links 18 have an adjustable lip 22 overlying the link 17, which permits the collapse of the linkage in one direction but limits the movement of the links around the pintle 21 in the reverse direction.

The linkage may be latched against collapse by the engagement of teeth 23 (Figs. 3, 5) on the links 17 with the peripheral surface of a shaft 24, journalled in the links 18, and having an armature fixed thereto between the links. The shaft 24 is cut away, intermediate its ends, to form on either side of the armature, a recess the passage of a tooth 23 when the armature 25 and shaft 24 are turned anti-clockwise to bring the slots 26 into registration with the teeth 23.

The armature 25 is normally biased, to move the peripheral surface of the shaft 24 into position for engagement by the teeth 23, by a spring 27, which is coiled around the pintle 21 and has one end engaging a tooth 28 on the armature 25 and its other end anchored under the pintle 19.

Clockwise movement of the shaft 24 is limited by the engagement of a stud 30 on the armature 25 with a stop 29 projecting from the link 18.

The armature 25 is composed of readily permeable material, such as soft iron, and depends from the shaft 24 below the linkage into the path of magnetic flux flowing between the bifurcated poles 31 and 32 of an electromagnet, which includes a non-magnetic tube 33 seated in an aperture in the magnetically permeable bracket 1 and solenoid coil 34 encircling the tube.

One end of the coil 34 is connected, through the pigtail 35, with the switch blade 7. The other end of the coil 34 is connected through the conductor 36 with an ex= ternal load terminal 37.

The pole piece 31 forms a part of the bracket 1, and the pole piece 32 is fixed to a magnetically permeable closure 38 at the outer end of the tube 33. The 1nn er end of the tube 33 communicates, through an opening in the bracket 1, with the non-magnetic cap 39, fixed to the bracket 1 and forming a chamber of larger cross-sectional area than the cross-section of the passage through the .0 tube 33.

A magnetically permeable core 40 is movable recti- 3 linearlyin the tube 33 and .cap 39 against the resistance of a coiled spring 41 and'of a fluid, or a thermally-fusible solid, s'a'lednri' thetube 33"'a'nd cap"39"'t'6' provide a dashpot action.

The core 49 has enlarged head 42 and a reduced nose 43 for makingclose magnetic'contact'with the bracket 1 and closure 38, respectively, when "the core is drawn into are solenoid coil 3410' its maximum extent, thereby decr'easing'the reluctance of the internal circuit of the magnet by closing'orshortening air gaps therein.

The armature 25' is so shaped and positioned that the poles 31 and 32, when energized, both exert a tractive 'f 'ee thereon in the same direction, viz., in an anti clocky direction in the 'position'shown in Fig. 1. This may b accomplished by slotting .the pole so that the bulge'25a is movable therein until the skirt 25b is in close juxtapositionto or contact with the vertically inclined faceof the space'betwecn and below the'bifurcations of the pole '31. The 'p'ole32' is more deeply slotted than the pole '31, and'the bulge 25c of the armature 25 lies therein so that upon anti-clockwisemovement of the armature its bottom surface comesinto relativcly'close juxtaposition to 'orcontact with the substantiallyhorizontal top surface of the .polepiece 32.

When the terminals 13 and 37 are connected in circuit and the switch blade '7 is'closed against the contact 9, current flows through the coil 34. The coil has such number of ampere turns that the magnetic flux created thereby, on the fiow of rated current, eXerts insuflicient attraction on the core 40 toovercome the resistance of the spring 511 and the dash pot fluid. When the current flow rises toward 125% 'of rated capacity, the flux generated :by the coil moves ,the core 40 .nto'the coil 34 at a rate proportionate to the overload. When the overload appreaches 125 %'of .rated capacity, the head 42 and the nose 43 will eventually 'contactihe bracket 1 and closure 38, thereby decreasing the reluctance of theniagnetic circuit between the members 1 and 38 and increasing "the magnetic flux betweenthe'pole' pieces 31' and 32 and through the armature 25.

' "This'increase in flux causes the armature 25 to rock anti-clockwise between the .pole pieces 31 and 32 and thereby rnov'e theshaft 24 so that slots 26 register with landpermit the passage 'df the teeth 23, as indicated in Fig.2. This permits the links 17 and 18 to collapse around the pintle 21under the'biasing action of the spring .1 on the switch blade 7, ,ith consequent opening of the switch blade 7 androcking of the handle 16 into open position 'as shown'in Fig. 4. The movement of the handle 16 into open position (Fig. 4) straightens the links 17 and 18 and causes the spring 27 to act ,on the tooth 2 8 and rock the armature 25 and shaft 24 into such position that the teeth 23 engage the peripheral surface of the shaft 24. The'switch blade 7 may be closed .by manually rocking the an le 16 abo s p v The interruption of the circuit between the contact 9 and contact -8 of the switch blade 7 interrupts the flow of energizing current through the coil 35!. The spring 41 thereupon expands and moves ,the core 40 back to its original position. Whencurrent flows in the coil 34 at a rate of or in excessof, the permissible overload of 125%, the core is moved faster than before toward the closure 38, and the flux generated will flow between the pole pieces 31 and 32 through the armature 25 at a density sufficient to rock the latter i to unlatching position before the nose 43 contacts the closure 38.

In the event of a shortcircuit, the flux density generated is sufiicient to rock the armature 25 before any substantial movement of the core 40 tak's place and tripping stress is thus applied to the armature 25 substantially concurrently with the rise of the currentflow in the coil 34, without the lag incident to the inertia and play of usual armature and tripping mechanisms.

Having described my invention I claim:

vl. A circuit' brea ker comprising a switchblade, collapsible linkage having one end connected .with said switchblade and through which said switchblade is closable, a

support for the other end of said linkage, a latch for holding such linkage in stress transmitting position, an armature connected with said latch and movable by said linkage, said-latch and armature being'supported solely by said linkage, 'and an Electra magnet in circuit with said switchblade and having a pole adjacent to said armature when said linkage is in stress'trans'miaing position.

: An.Q sr Qa 9ui breake s m ris i rt grown blade, a handle for operating said switchblade, collapsible linkage connecting said switchblade and handle, means ii-sensing"snieehsnien latcli'for'holding said'linkage in stress transmitting position, an armature supported solely by and movable with said linkage and operatively associated with said means, and an electro magnet in circuit with said switchblade and energized by current flowing therethrough to attract said'armature and therethrough actuate said means to permit the collapse of said linkage.

3. A circuit breaker comprising a switchblade, collapsible linkage having .o'neend connected with said switchblade and through which said switchblade is closable, a support for the other end of said linkage, a shaft journalled in said linkage and forming a latch member, an armature depending from such shaft and an electromagnet in circuit with said switchblade and having a pole adjacent to said armature in the stress transmitting position of said linkage.

4. Acircuit breaker comprising a switchblade, collapsible linkage having one end pivotally connected with said switchbladefa support for the other endof said linkage, said linkage comprising links having complementary latch members thereon respectively, an armature pivotally connected with and supported solely by said linkage and having means'engageablewith one of said latch members, and 'an electro magnet responsive to current flowing through said switchblade and having a pole adjacent to said armature when said linkage is in stress transmitting position.

5. A circuit breaker comprising a switchblade, linkage having one end pivotally connected with said switchblade, a support for the other end of said linkage, a latch controlling said linkage and including a shaft journalled in said linkage, an 'arfna't'ure supported solely by said shaft and movable to operatcisaid latch, means for biasing said shaft in one direction, a stop limiting the biasing action of said means and an electro magnet having a pole positioned adjacenttosaid armature for moving it contra said biasingime'ansl i 6.' A circuit breaker comprising a switchblade, collapsible linkage having ,one end pivotally connected with said switchblade, a'support for the other end of said linkage, the collapse of said linkage permitting movement of said switchblade, an armature supported solely by and controllingthe collapse of said linkage, and an electromagnet e e c lly ,QOH E ied with said switchblade and having a'bifurcated pole piece adjacent to said armature. '7.' A' circuit breaker comprising a switchblade and means for controlling the position of said switchblade, said means including an electromagnet having a coil connected with said swit hblade and pole pieces each having a section egrtending substantially parallel with the axis of said coil and sections extending transversely to the axis of said coil, one of the transverse sections of each pole piece being bifurcated, an armature pivotally connected with and moved by the movement of said switchblade, said armature being positioned between the bifurcations of said'sections when said switchblade is in closed positioiL'iand latch :pcrable by said armature to permit the uv' menr of said switchblade to open position.

8. circuitbreaker comprising a switchblade and means for controlling the position of said switchblade, said means including anelectrom agnet having a bifurcated pole piece, armature pivotally connected with and moved by the monement of said switchblade, said armature'having a nose 'movable 'between said bifurcations when said switchblade isclosed to permit the approach of a portion of said'armature' toward an unbifurcated portion of said polepiece, and a latch operable by the movement of said armature -to release said switchblade from its closed positionl' i 9. A circuitb er comprising a switchblade, collapsible linkagebaving" one end pivotally connected with said switchblade and through which said switchblade is closable, an electromagnet having a coil and opposite pole pieces extending transversely to the axis of said coil, an armature supported by said linkage in juxtaposition to both said pole pieces in the closed position of said switchblade and movable by said linkage away from at least one of said pole pieces upon the opening of said switchblade, and a latch operable by said armature for controlling said linkage;

(Mis ess s 91 f llowin page) 6 References Cited in the file of this patent 2,427,998 Wilcken Sept. 23, 1947 UNITED STATES PATENTS 2,529,662 PIPPOIJZI NOV- 14. 1950 1,731,391 Mottlau 06:. 15, 1929 FOREIGN PATENTS 2,072,932 Wilckens Mar. 9, 1937 5 260,966 Switzerland Aug. 1, 19 

